Depth of field objective

Abstract

The present invention relates to an objective for still cameras and motion picture cameras into which the critical focusing values of the two boundary points of a selected depth of field range are fed without being examined, whereupon the lenses and the diaphragm are adjusted automatically for a sharp reproduction of the respective range.

The invention is claimed as follows: 
     
       1. A method of preparing a photographic camera for the making of exposures of objects within a selected depth of field range between two boundary points, comprising the steps of focusing the lens system of the objective upon one of said boundary points, including moving the lens system in the direction of the optical axis to a first position; storing in the objective information denoting said first position; focusing the lens system upon the other boundary point, including moving the lens system of the objective in the direction of the optical axis to a second position; storing in the objective information denoting said second position; and thereupon utilizing the stored information denoting said first and second positions to automatically shift the lens system to an exposure position substantially midway between said first and second positions. 
     
     
       2. A method as defined in claim 1, further comprising the step of adjusting the diaphragm of the photographic camera in automatic response to shifting of the lens system to said exposure position so that the aperture size is a function of the exposure position of the lens system. 
     
     
       3. An objective for photographic cameras, comprising an optical system; means for focusing said optical system upon objects located at different distances from the objective, including means for moving said optical system in the direction of the optical axis; means in the objective for storing information pertaining to various positions of said optical system; means for actuating said information storing means; and means for automatically shifting said optical system to an exposure position substantially midway between spaced-apart first and second positions in each of which said information storing means was actuated so that the photographic camera embodying the objective is ready to make an exposure of objects located within the depth of field range bounded by points upon which said system was focused in said first and second positions thereof. 
     
     
       4. An objective as defined in claim 3, further comprising an adjustable diaphragm and means for adjusting said diaphragm in response to shifting of said optical system to said exposure position. 
     
     
       5. An objective as defined in claim 4, wherein said shifting means includes resilient means. 
     
     
       6. An objective as defined in claim 4, wherein said optical system comprises a rotary member and further comprising a base member supporting said rotary member, said information storing means including first and second rings respectively supported by said rotary member and said base member, each of said rings being rotatable relative to the associated member and said actuating means including arresting means for interrupting the rotary movements of said rings, said shifting means including means for turning said rotary member to the extent determined by relative angular positions of said rings upon interruption of the rotary movement thereof. 
     
     
       7. An objective as defined in claim 6, wherein said means for turning said rotary member includes a spring, one of said rings having an arm and the other of said rings having abutment means in the path of movement of said arm, said spring being arranged to move said arm against said abutment means or vice versa on disengagement of one of said arresting means.